1. The relationship between asthma and food allergy
Dr Deborah Marriage
Lead Nurse, Paediatric Allergy

2. Session aims Whistle-stop tour of IgE mediated food allergy
Anaphylaxis
Recognise increased risk of anaphylaxis in children with FA & asthma
Examine patient perceptions of the impact of foods on asthma
Consider a potential causal relationship between FA & asthma?
Examine the effect of co-morbidity on asthma
Identify risk factors
Think about management & treatment options

3. Definition of IgE-mediated allergy
‘An exaggerated sensitivity to a substance (allergen) not normally considered to be harmful, that is inhaled, swallowed or injected, or that comes into contact with the skin or eyes’.

4. What are the common culprits?

5. League table of food allergens (90% of reactions are caused by 7 foods)

6. Anaphylaxis
‘An acute, severe, life-threatening allergic reaction in pre-sensitised indivicuals, leading to a systemic response caused by the release of immune and inflammatory mediators from basophils and mast cells. At least 2 organ systems are involved’

7. Allergic asthma
The airway response to histamine is more sensitive in asthmatics
Allergen recognition leads to mast cells mediator production, ↑ histamine levels, inducing early phase bronchoconstriction and acute asthma symptoms
Late phase response due to chemotactic factors released by mast cells & inflammatory cell influx
4-6 hours after initial episode, eosinophils & neutrophils accumulate in the lungs causing oedema, tissue destruction and mucus production

8. Risk of anaphylaxis
Children with FA and asthma are at increased risk for severe anaphylaxis, including fatal events
This is compounded if asthma is poorly controlled
Food-allergy related fatalities
25 patients with sufficient information available
24 had asthma
Is this a causal relationship or coincidence?
Bock SA et al (2001) Fatalities due to anaphylactic reactions to foods. JACI

9. Asthma & Peanut Allergy
Symptoms of most recent reactions

10. Reaction Severity 3 Year UK Survey 1998-2000
(McDougall, Arch Dis Child 2002)

11. UK Mortality data 8 paediatric deaths in 8 years (1990-1998) - 4 milk
- 2 peanut (>13 years)
- 2 pretreated with Epipen
- 1 adrenaline overdose (iv by medic)
- Asthma strongly associated
6 severe / 49 near fatal reactions
- 10 peanut
- 14 tree nuts
 Risk of death 1: /yr
(Hourihane, ADC 2002)

13. What is the role of FA in asthma?
Several studies examine the role of FA in asthma development
Co-existence increases the severity of both disorders
Risk even greater when food allergy is multiple or severe

14. Patient Perception

16. Patient Perception
20-60% people report food as a trigger for asthma but only 2.5% react to DBPCFC
Australian survey 156 asthma clinic patients
73% believed food induced their asthma symptoms
61% had attempted to modify their diet
79% of those reported improved asthma control
(Woods PK et (1996) Patients’ perceptions of food-induced asthma. Aust N Z J Med)

17. Effect of FA upon asthma morbidity
FA independently associated with ↑asthma
Children with FA & asthma ↑ asthma morbidity than asthma alone
Higher rates of hospitalisation
Higher oral steroid requirements
↑ rate of severe asthma exacerbations (OR 6.)
↑ rate of life-threatening asthma
Gonzalez-Perez, A et al (2010) Anaphylaxis epidemiology in patients with and without asthma: a UK database review JACI
Roberts GC et al (2003) Food allergy as a risk factor for life-threatening asthma in childhood. JACI
Wang J et al (2005) Food allergen sensitization in inner-city children with asthma. JACI
Savage JA et al (2007)The natural history of egg allergy. JACI
Liu AH (2010) National prevalence and risk factors for food allergy and relationship to asthma. PAI

18. Asthma Management Options
Do children with FA & asthma require more aggressive asthma management than asthmatics without FA?
↑ FENO
↑ sputum eosinophils
In adults, ↑FENO, Airway Responsiveness (AR) & circulating eosinophils associated with + SpIgE to 6 foods
Caffarelli C (2012) Hydrogen peroxide in exhaled breath condensate in asthmatic children during acute exacerbation and after treatment. Respiration
Patelis A (2014) Aeroallergen and food IgE sensitization and local and systemic inflammation in asthma. Allergy

19. What is the link between FA & Asthma?
Association between FA & Asthma stronger when subjects stratified for concurrent aeroallergen sensitisation
Penard-Morand C et al (2005) Prevalence of food allergy and its relationship to asthma and allergic rhinitis in schoolchildren. Allergy

20. Is greater atopy merely associated with severe, persistent, earlier-onset asthma and food sensitisation or is there a direct causal relationship?

21. Food allergy & Prediction of asthma development
Allergic March
IgE food sensitisation linked with wheeze at age 7
Multiple studies have confirmed the risk for asthma is greater in infants with eczema, multiple food sensitisation & filaggrin mutation

22. Food allergy risk factors for asthma

23. Egg allergy Seems to be more relevant that allergy to milk
+SPT to egg in 1st year of life is predictive of adult asthma (OR 10.7)
Children with an atopic family history or wheezing who have egg allergy are more likely to develop asthma
Tariq SM et al (2000) Egg allergic in infancy predicts respiratory allergic disease by 4 years of age. PAI
Gaffin JM et al (2011) Tree Nut Allergy, Egg Allergy, and Asthma in Children. Clin Pediatr.

24. Milk allergy
Milk allergy at 7/12 associated with ↑ BHR and FENO at age 8.
Sever asthma may be a predictor for persistent CMPA.
Saarinen KM et al (2005) Clinical course and prognosis of cow's milk allergy are dependent on milk-specific IgE status. JACI
Malmberg LP et al (2010) Cow's milk allergy as a predictor of bronchial hyperresponsiveness and airway inflammation at school age. CEA

26. Severe allergens
Some allergens are more commonly linked with severe allergic reactions than others

28. Less obvious manifestations

29. When to suspect FA in asthmatic children
Acute life-threatening asthma with no identifiable triggers
Highly atopic children with severe persistent asthma resistant to therapy who give poor clinical histories (ie children in care)

30. Airborne food allergens
Inhaled food molecules can provoke severe reactions in allergic children eg cafes, fish market
Caused by cutting, boiling or steaming
Some clinical reactions (esp fish or shellfish) may be more severe than when taken orally
Some may only cause reactions when inhaled
DPIs containing lactose do not usually cause reactions but in severe milk allergy and asthma chest tightness, ↓BP and FEV1 have been reported from some lots of Seretide

31. Food-dependent, exercise-induced anaphylaxis (FDEIA)
Food intake or exercise alone does not induce symptoms
Anaphylaxis triggered by exercise only when child ingests a particular food (often wheat)
Not always reproducible; may be mild or strenuous exercise
Half present with cough, chest tightness or wheeze
reduction in FEV1 on those without respiratory symptoms

32. Implications for practice
FA & asthma co-exist in many children
Increased risk of food anaphylaxis in asthmatic children
FA children conversely also likely to have severe asthma
Accurate diagnosis of both FA & Asthma essential
Increased awareness of the heightened risks of having both conditions + good family education can lead to improved outcomes
Allergy Action Plan
Personalised Asthma Action Plan
Training for any AAI prescribed
Written supporting information (Allergy UK; Anaphylaxis Campaign)

34. Emergency Medication

35. Conclusion
FA & Asthma places children at greater risk for morbidity and mortality, particularly if asthma in uncontrolled
Heightened awareness of the relationship between them is important & recognition may improve treatment and prevent severe reactions
Consider FA in children with life-threatening asthma
Such children require AAIs (with training!)
A multi-faceted approach leads to optimal care
Family education is paramount

36. Thank you!